Very Lazy Edition: Coil-Shortened Dipole Antenna Calculator https://www.66pacific.com/calculators/coil-shortened-dipole-antenna-calculator.aspx
Previous Thread: >>2974159
>New to /ham/? Read this shit! http://www.arrl.org/what-is-ham-radio https://www.fcc.gov/wireless/bureau-divisions/mobility-division/amateur-radio-service >Your search engine of choice works well too!
>The wiki is down but is archived https://archive.is/PjR5s >NEW FAQ is updated to preview 15 https://files.catbox.moe/aftx43.htm
>Online Practice Tests: http://aa9pw.com/ https://hamstudy.org/ https://hamexam.org/ > Real-Time Propagation Data http://prop.kc2g.com/ https://www.ham-stream.com/ >Space Weather https://www.swpc.noaa.gov/communities/radio-communications https://www.solarham.com/ >point to point predictions, its free and will give you an idea of how much power/ what frequencies to use to reliably talk to your friend https://www.voacap.com/hf/ >WSJT-X Home Page https://wsjt.sourceforge.io/wsjtx.html >Homosexual (ft8) guide https://www.g4ifb.com/FT8_Hinson_tips_for_HF_DXers.pdf >APRS http://www.aprs.org/ >Weather Fax resources https://www.weather.gov/media/marine/rfax.pdf https://weatherfax.com/stations/ >how do I into Morse code in a good way? https://pastebin.com/HByjfN4F
Stand-by, I have to QSY. Comms are being interferred with by the incessant, non-stop digital drone of %&*@! computers slowly texting “599” to each other.
>local fire >major damage >fire still spreading >ARES activates >gets in the way just to make themselves seem relevent I wouldn't be surprised if they started the fire.
>>2987941 I don't. I got tired of them parroting the same exact stuff as if every single one of them got the same script to read from.
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Anonymous04/26/26(Sun)22:29:00
is it worth it saving up for one of the more expensive radios like icom 7300 or something second hand? i see that they have unlockable vfo. do most other radios have that too? also, having a built in antenna tuner is very good. thats just an example
what is the cheapest radio that has built in antenna tuner and unlockable vfo? i mean using 22m or 45m or 11m + the standard ham bands.
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Anonymous04/26/26(Sun)22:37:04
any opinions on xiegu g90? i see one second hand for 200
>>2987996 >what is the cheapest radio that has built in antenna tuner and unlockable vfo?
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Anonymous04/27/26(Mon)06:28:13
>>2988026 i think xiegu g90 fits the bill. it also has an swr scan which is handy. the one for 200 is gone. it was cheap.
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Anonymous04/27/26(Mon)21:44:46
could some kind anon post a problem for me, I have with a hermes lite 2 sdr, on the support google group? I managed to never have had such an account and they offer no other option. It would be much appreciated and I offer one or two internets as a thankyou gift.
>>2988098 you must be some kind of a popular fellow ..
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Anonymous04/29/26(Wed)19:01:08
>>2988101 do shit yourself. no one wants to be the middleman in this thread and another thread.
what a stupid thing to ask.
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Anonymous04/30/26(Thu)21:27:33
>>2987996 >what is the cheapest radio that has built in antenna tuner and unlockable vfo? The cheapest is the one you make yourself. Last thread had some practical links. >i mean using 22m or 45m or 11m + the standard ham bands. Those are some unusial bands, what are you planning?
>Very Lazy Edition: Coil-Shortened Dipole Antenna Calculator >https://www.66pacific.com/calculators/coil-shortened-dipole-antenna-calculator.aspx Hey! An edition based upon my post!
Btw, it didn't work. Instead, I just coiled so much on 4in diameter pipe 1ft long (R came out to be around 200), center placed the coil, the tuned at the last part. It's sweet spot is 1.945. Thamks to a tuner, the gentlemen's band is now covered. Even interrupted the only conversation on the band to ask for a signal report: around 55. Lol, as expected.
80m and 40m needs some tuning bit still work with an swr of around 3. 20m is spot on at 1.3.
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Anonymous05/03/26(Sun)19:30:14
What would a signal look like if you apply a sine audio into a SSB transmitter? The immediate answer would be that it looked like a sine shifted up, yet when you key the sighnal on/off, there is a transition. For an AM signal it would go either side of the carrier, but on a SSB it would be to one side only. So for USB it should be on the upper side of the sine signal, right? So for that reason the signal has to be a bit more involved. Anyone got a clue? The ham stackexchange was no help.
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Anonymous05/04/26(Mon)22:32:33
>>2989067 maybe they would have been more helpful, if you'd be able to ask a proper question.
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Anonymous05/05/26(Tue)00:26:30
>>2989067 Do you know what fourier and inverse fourier transforms look like? Or how sine waves multiply?
If you have a 1kHz audio sine, modulating with a 1MHz carrier via AM, then you'll get a 1MHz sine wave that varies in amplitude at 1kHz, without crossing zero. The envelope will just be a 1kHz sine wave. Because of beat-frequencies. The keying on of this signal will look like two sidebands increasing in volume. output = (A*sine(1kHz) + C) * B*sine(1MHz) = A*B*sine(1MHz + 1kHz) + A*B*sine(1MHz - 1kHz) + B*C*sine(1MHz)
If you remove the carrier wave so you have AM/double-sideband suppressed-carrier, you'll get a 1MHz sine wave that varies in amplitude at 1kHz crossing zero. The envelope will look like it's full-wave rectified 1kHz sine wave. output = A*sine(1kHz) * B*sine(1MHz) = A*B*sine(1MHz + 1kHz) + A*B*sine(1MHz - 1kHz)
If you then remove the lower side-band so you just have the upper sideband, you'll be left with a 1.001MHz sine wave. The envelope will be flat, DC. In order to demodulate this, you need to know which frequency it's actually meant to be transmitting on. If you tune your radio to 1.0005MHz instead of 1MHz, you'll hear a 500Hz sine instead of 1kHz. output = A*B*sine(1MHz + 1kHz)
For any suppressed-carrier AM modulation method, be that single or double-sideband, ideally no power is transmitted when no audio is being modulated. When A=0, output=0. This is one of the motivating factors behind suppressed-carrier transmission, to use less power to get the same signal across. So the keying on of any suppressed-carrier's audio waveform will just look like the sideband(s) rising from zero, not transitioning from any carrier.
>>2989527 >what the signal would look like in time domain A quickly rising and falling amplitude of a sine wave. Be that at 1khz after being demodulated, or 1.001MHz before being demodulated. Pic related.
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Anonymous05/07/26(Thu)12:04:01
>>2989533 It'd be easier to make the bridge an efhw. Hopefully you have a great atu because matching that is going to be a bitch.
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Anonymous05/07/26(Thu)20:44:04
just had my first brief and mostly one sided qso on 11m. some brit cqd on 27.555, said he would monitor 27.485. i went there and replied. he could barely hear my call sign but got the division prefix and the numeric part of the callsign. on receive it was much better though.
i think its because the radio is in dire need of maintenance, probably some caps and alignment but regardless, i'm happy for the semblance of a qso.
tonight i'm constantly hearing uk and ireland. some noticeable propagation is going on.
>>2989755 Interesting. Looks a bit like one of those phased array antennas except with really complex “pads” I tried tracing their PCB design and came up with picrel.
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Anonymous05/08/26(Fri)15:32:30
>>2989802 I try not to think about it, the demons can see you if you.think about them.too.mvuh
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Anonymous05/08/26(Fri)18:01:09
I am sitting in the dark listening to BPM China because my electricity is out. No hint of Jane Barbe tonight though.
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Anonymous05/09/26(Sat)17:36:03
i'm starting to narrow down my choice to the Kenwood TS450(S)
anyone used these or similar models ts690 etc?
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Anonymous05/09/26(Sat)20:17:44
>>2989570 The rising and falling parts are the ones that will cause sidebands, and on an upper sideband you will, strangely, get just get a sideband tail to the right on a waterfall diagram. And there is no way a sine wave will be able to do that. This is a hard question.
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Anonymous05/10/26(Sun)08:52:48
>>2989975 The changing amplitude of a sine wave, when you take the fourier transform of it, will look like a collection of harmonics alongside the sine's main frequency spike. That's just how fourier transforms, and hence waterfalls, work. The slower the transition, the less significant those harmonics will look. With a really fast transition (significantly faster than the rise on an equivalent constant-amplitude sine), you get a bunch of higher harmonics going off by something like 20dB/dec. The fourier transform of a step response. With a slow transition, you'll get splitting of your 1.001MHz sine into miniature side-band-like things, and the slower the transition the closer these are together.
Would be fairly easy to do in python or matlab or whatever, just generate a sine wave multiplied by some sort of keying function (e.g. atan(w*(t-t0))/pi + 0.5 ), and FFT it. You may want to add a windowing function if the beginning and end don't line up.
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Anonymous05/10/26(Sun)15:45:03
finally after 2 (two) months of monitoring the vhf repeaters by the 3-3 rule i heared two boomers talk something happened, vhf is not dead
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Anonymous05/10/26(Sun)21:41:43
>>2990037 >Would be fairly easy to do in python or matlab or whatever OK, please do. Say, a 1 kHz audio modulated to upper sudeband at 10 MHz, with a sinc shaped keying on/off, and then show the time domain signal.
>>2989722 Nice. For a while when I first got on HF I could hear decently but couldn't be heard well. Turned out I needed a groundplane for my vertical I was using. After that it was much better.
>>2989838 >skree... skree... skree... skree.. I spent friday night out in the boonies monitoring WxFax transmissions out of Alaska, Hawaii, and California plus some NAVTEX. Also a bit of listening to VLF and LF beacons and some AM BCB monitoring. Clear night, good conditions on the bands while nursing some beers with my Coleman lantern hissing away. Comfy.
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Anonymous05/11/26(Mon)00:09:01
>>2989956 Yes. I bought my TS-690S new in '93. I still have it and it's still my No.1 favourite radio in my small collection. I've also played with a TS-850S and a TS-440S to a limited extent.
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Anonymous05/11/26(Mon)15:07:17
>>2990124 i'm using a horizontally pol. full wave loop. dont think it needs a ground plane
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Anonymous05/11/26(Mon)15:15:11
>>2990127 i see these going for 400-500 usd. they look interesting. with vox, it would be easier to do digimodes and 100w is perfect for most uses.
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Anonymous05/12/26(Tue)05:40:11
>>2990201 They're pretty decent radios and still hold their own today. If you do voice work, they're legendary for their audio. Unless you get an abused unit, I don't think you'll regret owning one.
But they are getting up there in age so look out for leaking capacitors and the back-up battery. Not that it's common, but it does happen. Otherwise there are 2 weaknesses to be aware of. It's recommended that if C104 on the IF board is original (brown case) to change it out with a 25 V one, preferably with a Panasonic brand. They say if it hasn't leaked yet, it will. The originals are rated at 10 V but often get spiked at 14 V. It's easy to access so no fears about a complete radio tear-down. Flip the radio over and open the access panel, the capacitor is right there near the filter slots.
The other thing to be aware of is that it uses proprietary DDS chips. The early chips were the 6631's and the later 66312's. The 6631's supposedly had a flaw and were prone to failure yet I don't know any 450S/690S owners that experienced that. My radio has the early DDS chips. Up to a few years ago you had to find a parts donor if you needed to replace it. I stumbled on a local parting a TS450S and I snagged the DDS board for cheap just in case. Regardless, there is an outfit in Italy called RF Systems that sells aftermarket boards.
I did RTTY and PSK31 with mine. I recommend getting the CW filters for both IF's for narrow-band digital work. Inrad's if you can afford them. And finally, but not lastly, you can do computer control relatively easy if you are into that. I never did so I have no insight into that.
Hope this helps.
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Anonymous05/12/26(Tue)05:54:59
>>2990308 thanks for the tips, yeah i kind of expect to change a few caps in older electronics. in around 1990, the battery backed memory was pretty common in all kinds of electronics. i had to change the cr2033 on two synthesizers before. caps are no problem either. the worst problem would be that special chip youre referring to
>>2990382 I've never done one to it yet. I lack a signal generator but am on the lookout for one. I'm also thinking about getting an aftermarket TCXO for it.
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Anonymous05/15/26(Fri)12:11:55
Hey guys, any ideas on how to use LoRa tech to help out campers near a national park? I read you could set up a "wifi" access point where people could send basic text messages that can bounce all the way to the city. Seems neat.
>>2990900 Can be done with a system like Meshtastic or Rnodes. But each user needs a LoRa terminal of their own. The common method is for the LoRa terminal to Bluetooth to your phone, and the app on your phone is used for interfacing with it to send and receive messages. But I believe you can also buy standalone terminals. A stand-alone terminal at each tramping hut might be sensible, assuming there isn’t already a method for emergency communication there. Lending terminals to trampers might be feasible, they come out to something in the ballpark of $20-40 for a Bluetooth model. Heltec and Lilygo make decent ones IIRC.
LoRa terminals have decent range, but the real power is in their ability to hop from node to node. To properly take advantage of this you’d either need lots of spread out people with these at any time, or to set up repeater nodes, probably with solar and batteries, atop nearby hills.
And then at the receiving end, back in civilisation, you’d need to figure out what to do with the messages. It’s not like they’re SMS texts sent via a SIM. Maybe you turn them into emails, or just use them for emergency comms.
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Anonymous05/16/26(Sat)01:30:44
>>2991101 don't bump here, this thread will be around for months... unfortunately.